In automotive controllers with displays such as radio or heat and air conditioning controllers it is commonplace to employ manually operated push button switches for controlling various functions and a lighted display bearing information related to the control status. Commonly the switches comprise conductors on a printed circuit board and a conductive elastomeric switch pad with pushbutton features overlying the circuit board to selectively bridge adjacent conductors. Typically the switch pad is a molded gray silicone rubber material. Liquid crystal displays (LCDs) are often used for the displays and the illumination is provided by back lighting.
The back lighting is implemented by a lamp or lamps at the rear of the display unit and a reflector behind the lamps to increase the efficiency and the uniformity of the illumination. Usually a molded white plastic reflector is positioned at the rear of the display and is mounted on or adjacent the circuit board; in some cases the circuit board has an aperture at the display site and the reflector is behind the aperture and the display is in or in front of the aperture. In either case the switch pad has an aperture at the display site to accommodate the rear lighting scheme.
Since the switch pad and the reflector are juxtaposed in the controller assembly, it is desirable to combine them to reduce the number of parts in the assembly. Such reduction eliminates the tooling, manufacture, inventory and assembly of one of the parts, thereby reducing the cost of the assembly.